The present invention relates to frequency modulation (FM) demodulators and more particularly to a simplified circuit technique implementable in integrated circuit structure for converting an analog FM signal to a digital representation of the analog modulation signal component of the FM signal.
The invention is particularly useful in telecommunications, television, radio satellite communication applications and, in general, in any FM receiver utilizing digital signal processing technology.
FIG. 1 is an FM demodulator arrangement for converting an analog FM signal to a digital signal representative the analog modulation signal component of the FM signal known in the prior art. An analog FM input signal from the IF stages of an FM receiver is demodulated by an analog FM demodulator 1 whose output is de-emphasized in the equalizer 2 to remove the pre-emphasis effect provided in the transmission of the FM signal to enhance the signal-to-noise ratio thereof. Finally, the demodulated and equalized analog signal is converted to a digital signal at the analog-to-digital converter 3. The technique of the prior art as shown in FIG. 1 requires many analog components because each of the circuits 1, 2 and 3 provide a function separately and independently one from the other.